Axially biased segments for circumferential seal in air heater rotor



y 2, 1958 .J. c. VICKLAND AXIALLY BIASED-SEGMENTS FOR CIRCUMFERENTIAL SEAL I-N AIR' HEATER ROTOR Filed June 29. 1953 IN VEN TOR Jo/m C. Wei/and 23 A TT ORNE Y United States Patent AXIALLY BIASED SEGNIENTS CIRCUMFER- ENTIAL SEAL 1N AIRHEATER ROTOR Application June 29, 1953, Serial No. 364,806

1 Claim. (Cl. 286-23) This invention relates to rotary regenerative air preheaters or like apparatus and particularly to improved circumferential seals for use between the rotor and the housing that encloses it.

In a rotary regenerative heater a cylindrical rotor is divided into compartments that carry heat transfer material which as the rotor turns is first exposed to the heating gases and then disposed in the air passage to impart the absorbed heat to the air. The rotor is surrounded by a housing having end or sector plates formed with openings to provide for the flow of gas and air and in order to preclude the flow of gas or air through the clearance space between the housing and .the side of the rotor in a way to bypass the heat transfer material, it is customary to provide the rotor with circumferential seals that bear against the end plates or other stationary parts.

The present invention contemplates improved circum- :ferential sealing devices of novel form that are divided into arcuate sections each of which is individually biased against the adjacent end plate of the housing. The invention may be better understood upon consideration of the following detailed description of an illustrative embodiment thereof when read in connection with the accompanying drawings in which:

Figure 1 is a sectional elevational view of the spring biased seal in cooperative engagement with an arcuate sealing segment.

Figure 2 is a fragmentary plan view of adjacent sealing segments comprising the sealing member.

Figure 3 diagrammatically represents a sealing segment showing the positioning of its driving pins relative to its center of gravity.

In the drawings numeral 20 indicates the cylindrical shell of a rotor which turns on its axis in a housing 30 provided at opposite ends with end plates 36 apertured at 42 to permit streams of gas or air to flow through the rotor of the preheater.

In order that the stream of gas and air may not bypass the heat transfer surface 14 by flowing in the annular clearance space 24 between the rotor shell 20 and the housing 30, it is customary to provide circumferential seals on the shell 20 which wipe against imp'erforate portions of the sector plates 42 or allied parts so as to seal off the space 24 at both ends of therotor. According to the present invention, the improved form of circumferential seals consists essentially of arcuate sealing segments preformed to cooperate with rotor shell 2-0 and the end plates 36 so as to confine the gases flowing through the rotor of the preheater to their prescribed channels.

Each arcuate sealing segment 62 has a plane edge 64 adapted to bear and seal against an inner face 65 of end plate 36. The arcuate lip 66 of the segment 62 is adapted to fit closely adjacent the arcuate surface 70 of a seal bracket 68. At each end of the sealing bracket are located driving pins 72 fixed to flange 74 of the sealing segment 62. These pins 72 are adapted to slide freely through openings 75 drilled in flange 76 of the arcuate "ice 2 sealing bracket 68. The flange 78 of the sealing bracket 68 is arcuately shaped to conform with the inside radius of the rotor shell 20.

Adjacent each driving pin 72 is a spring means 82 firmly fastened to flange 76 of sealing bracket 68 by means such as the screw 84 illustrated. The free end-"of spring 82 is bifurcated at 87, the bifurcate tines straddling the pin 72 and bearing, upwardly in Figure 1, against flange 74 of sealing segment 62 to bias the plane edge 64 into sealing engagement with the inner face 65 of sector plate 36. A spring means 82 is positioned at each pin 72.

Each sea-l segment 62 together with a corresponding sealing bracket section 68 are handled as a composite unit, the pins 72 being inserted in opening 74 and the cooperating units squeezed together compressing the spring 82 thereby permitting the said unit to be inserted through v the opening 42 into the space between end plate 36 and the end edge of rotor shell 20. Rotor shell 20 is drilled at a plurality of spaced points 85 adjacent its end edges to accommodate bolts 88, the heads of which are preferably tack welded to the shell 20 so that during assembly the bolts are not displaced from their proper position and the sealing bracket 68 having openings 86 may be readily matched with the bolts 88, and the nuts 90 aflixed thereto so as to positively hold the sealing bracket integral with the inner peripheral edge of the rotor shell in the manner shown in Figure 1.

An important consideration in locating the pins 72 is that they be located in arcuate alignment adjacent opposite ends of a sealing segment 62 whereby the center of gravity of each segment lies in or adjacent a straight line connecting the pins in the manner illustrated by Figure 3. By such an arrangement there will be little or no tendency 'for a seal member 62 to tilt, and the pin 72 will not bind as it slides in opening 74, the outer peripheral edge of lip '66 will move freely along and inwardly of surface 70, and the sealing edge 64 will evenly abut the inner plane surface 65 of sector plate 36.

As seen in Figure 2, alternate sealing segments are preferably cut so that the inner arcuate edge is shorter than the outer edge. By such an arrangement, no difliculty is experienced in progressively assembling from inside the rotor, the combined sealing bracket and sealing segment into a composite circumferential seal between the rotor shell 20 and the sector plate 36.

A circumferential seal of the type herein disclosed may be used adjacent the upper edge of the rotor shell in the manner herein disclosed and it may also be used at the lower edge of the rotor shell adjacent the lower end plate. When used adjacent the lower portion of the rotor, the assembly is obviously inverted so the sealing segment 62 will be gravity biased into contact with the inner face of end plate 36. Under such conditions the spring 82 might be omitted, as the gravitational force acting upon the sealing segment may be suflicient to bias said segment into contact 'Wllh the lower end plate. Under certain conditions however, the sealing segment may be weighted to further increase the biasing force tending to hold the sealing segment against said lower end plate.

What I claim is:

A sealing device adapted to preclude the flow of gaseous fluid between fixed and relatively movable housing members comprising; an annular sealing bracket concentrio with the rotatable housing member and fixed to an end edge thereof, said annular sealing bracket including a lateral flange extending radially outward between the relatively rotatable members; an arcuately divided sealing ring bridging the space between the annular sealing bracket and the fixed housing members adapted to provide a series of sealing segments including integral flanges extending radially outward into axially spaced relation with the flanged portion of the sealing bracket; and positioning and driving means comprising a pair of pins extending axial-1y between each segment of the sealing ring flange and the flanged portion of the sealing bracket and connecting said sealing bracket and said sealing ring segments for relative axial movement, said driving means being arcu'ately spaced to permit the center of gravity of each arcuate segment to lie adjacent a straight line extending therebetween.

References Citedin the file of this patent UNITED STATES PATENTS Erisman Aug. 1, Jensen 'Aug. 19, Hodson Mar. 17, Flurschutz Oct. 26,

, FOREIGN PATENTS Great Britain Mar. 22, 

